ADDED before/after string functions.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/15831

common/text_eval/text_eval_parser.cpp

@@ -521,6 +521,34 @@ auto EVAL_VISITOR::evaluateFunction( const FUNC_DATA& aFunc ) const -> Result<Va
 
             return MakeValue<Value>( result );
         }
+        else if( name == "beforefirst" && argc == 2 )
+        {
+            wxString result = VALUE_UTILS::ToString( argValues[0] );
+
+            result = result.BeforeFirst( VALUE_UTILS::ToString( argValues[1] )[0] );
+            return MakeValue<Value>( result.ToStdString() );
+        }
+        else if( name == "beforelast" && argc == 2 )
+        {
+            wxString result = VALUE_UTILS::ToString( argValues[0] );
+
+            result = result.BeforeLast( VALUE_UTILS::ToString( argValues[1] )[0] );
+            return MakeValue<Value>( result.ToStdString() );
+        }
+        else if( name == "afterfirst" && argc == 2 )
+        {
+            wxString result = VALUE_UTILS::ToString( argValues[0] );
+
+            result = result.AfterFirst( VALUE_UTILS::ToString( argValues[1] )[0] );
+            return MakeValue<Value>( result.ToStdString() );
+        }
+        else if( name == "afterlast" && argc == 2 )
+        {
+            wxString result = VALUE_UTILS::ToString( argValues[0] );
+
+            result = result.AfterLast( VALUE_UTILS::ToString( argValues[1] )[0] );
+            return MakeValue<Value>( result.ToStdString() );
+        }
 
         // Conditional functions (handle mixed types)
         if( name == "if" && argc == 3 )

qa/tests/common/text_eval/README.md

@@ -11,7 +11,7 @@ High-level integration tests using the `EXPRESSION_EVALUATOR` wrapper class.
 - **Variable Substitution**: Testing variable storage and retrieval in expressions
 - **String Operations**: String concatenation, mixed string/number operations
 - **Mathematical Functions**: `abs`, `sqrt`, `pow`, `floor`, `ceil`, `round`, `min`, `max`, `sum`, `avg`
-- **String Functions**: `upper`, `lower`, `concat`
+- **String Functions**: `upper`, `lower`, `concat`, `beforefirst`, `beforelast`, `afterfirst`, `afterlast`
 - **Formatting Functions**: `format`, `fixed`, `currency`
 - **Date/Time Functions**: `today`, `now`, `dateformat`, `weekdayname`
 - **Conditional Functions**: `if` statements with boolean logic
@@ -69,6 +69,10 @@ Integration tests simulating real-world KiCad usage scenarios:
 - `upper(str)` - Convert to uppercase
 - `lower(str)` - Convert to lowercase
 - `concat(...)` - Concatenate multiple values
+- `beforefirst(str, c)` - Substring
+- `beforelast(str, c)` - Substring
+- `afterfirst(str, c)` - Substring
+- `afterlast(str, c)` - Substring
 - `format(num, [decimals])` - Format number with specified precision
 - `fixed(num, [decimals])` - Fixed decimal formatting
 - `currency(amount, [symbol])` - Currency formatting

qa/tests/common/text_eval/test_text_eval_parser.cpp

@@ -288,6 +288,12 @@ BOOST_AUTO_TEST_CASE( StringFunctions )
         // String concatenation function
         { "@{concat(\"Hello\", \" \", \"World\")}", "Hello World", false },
         { "@{concat(\"Count: \", 42, \" items\")}", "Count: 42 items", false },
+
+        { "@{beforefirst(\"hello.world.txt\", \".\")}", "hello", false },
+        { "@{beforelast(\"hello.world.txt\", \".\")}", "hello.world", false },
+        { "@{afterfirst(\"hello.world.txt\", \".\")}", "world.txt", false },
+        { "@{afterlast(\"hello.world.txt\", \".\")}", "txt", false },
+        { "@{beforefirst(${text}, \" \")}", "hello", false },
     };
 
     for( const auto& testCase : cases )